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      • KCI등재

        Synthesis and Gas Adsorption Properties of Carbide-Derived Carbons from Titanium Tin Carbide

        Yuanyuan Zhu,Aiguo Zhou,Jin Jia,Junjun Wang,Jiang Liu,Baolin Xing,Chuanxiang Zhang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.4

        Here we reported the synthesis of nanoporous carbide-derived carbons (CDCs) from a new precursor, titanium tin carbides (Ti2SnC), via chlorination at 400–1100℃. At low chlorination temperature (400–500℃), as-synthesized CDCs mainly consisted of amorphous carbon and chlorides. As the chlorination temperature increased up to 600℃, chlorides disappeared, and the main composition of CDCs was amorphous carbon. At high chlorination temperature, there was a trend of graphitization. The microstructure of CDCs was observed and characterized by scanning electron microscopy and transmission electron microscopy. Some graphite-like sheet structures in CDCs were found. Specific surface area (SSA) and pore volume of CDCs increased with chlorination temperature, except an abnormal decrease of the CDC chlorinated at 900℃. CDC chlorinated at 1100℃ had the largest SSA, 1580 m2 /g. In order to apply these materials as novel hydrogen/methane storage media in the area of energy efficient transport, gas adsorption properties of CDCs were measured. For CDC chlorinated at 1100℃, pore volume uptakes are 206 cm3 /g at 60 bar (25℃) for methane, and ~442 cm3 /g at 35 bar (-196℃) for hydrogen, respectively. It was suggested that CDCs from Ti2SnC are promising materials for hydrogen/ methane adsorptive storage.

      • KCI등재

        Oil film stiffness and damping in an elastohydrodynamic lubrication line contact-vibration

        Yuanyuan Zhang,Hua iju Liu,Caichao Zhu,Mingyong Liu,Chaosheng Song 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.7

        An elastohydrodynamic lubrication line contact-vibration model is proposed to study the stiffness and damping of the oil film existed in the EHL contact region. An initial mutual approach between interacting surfaces, which deviates from the steady-state balanced position, is assumed under the free contact-vibration to predict the response of the mutual approach. An inertia term, which represents the acceleration of the gap motion, is added to the classical force balance equation to form the equation of motion of the mutual approach. Response of the mutual approach is solved based upon the solving of the contact-dynamic model. The oil stiffness is calculated according to the natural frequency of the response under damped and non-damped conditions, the latter of which represents dry contact conditions. The oil film damping is calculated in terms of the principle of the energy conservation which utilizes the whole history of response compared with the log decrement method. Effect of the normal load, the rolling speed and the amplitude of the regular sinusoidal surface waviness on the oil film stiffness, the contact stiffness and the oil film damping are studied. The study provides an insight on the oil film dynamic characteristics of lubricated contact-vibration problems which appear in gears, bearings, etc. The results show that the oil film damping factor decreases with the increasing normal load as well as the increasing rolling speed. The oil film stiffness increases with the normal load and decreases with the rolling speed. Also, compared to the contact stiffness, the oil film stiffness makes less contribution to the total stiffness. The surface waviness amplitude has little effect on the oil film stiffness and the oil film damping.

      • KCI등재

        Dynamic changes in carbohydrate metabolism and endogenous hormones during Tulipa edulis stolon development into a new bulb

        Yuanyuan Miao,Zaibiao Zhu,Qiaosheng Guo,Xiaohua Yang,Li Liu,Yuan Sun,Changlin Wang 한국식물학회 2016 Journal of Plant Biology Vol.59 No.2

        The stolon is the main asexual reproductive organ of Tulipa edulis (Miq.) Baker. It has a special morphology and can develop into a new bulb for propagation. In the current greenhouse experiment, the dynamic changes in carbohydrates and related enzymes, protein and endogenous hormones during T. edulis stolon development were investigated. The results showed that soluble sugar levels were basically declining, whereas starch and protein content rose continuously during stolon development. The adenosine diphosphoglucose pyrophosphorylase (AGPase) activity peaked in the initial swelling stage and stayed a relative high level in the middle swelling stage; sucrose synthase (SS), soluble starch synthase (SSS) and granule-bound starch synthase (GBSS) activities followed the same law that showed rising trends during stolon development. SS activity was significantly inversely related to sucrose content but had significantly positive relations with starch content, SSS and GBSS activities. Gibberellin (GA), indole-3-acetic acid (IAA) and zeatin riboside (ZR) peaked in the initial swelling stage and maintained high levels in the middle swelling stage; they then decreased significantly in the later swelling stage. A substantial increase was observed in abscisic acid (ABA) content until the middle swelling stage, followed by a significant reduction in the later swelling stage. The ratios of ABA to IAA, GA and ZR reached their lowest levels in the initial swelling stage. In conclusion, T. edulis stolon development is a process of new bulb morphogenesis along with the starch accumulation catalyzed by AGPase, SSS and GBSS, using the product of sucrose cleavage caused by SS. Initial low ABA content and low ratios of ABA to IAA, GA and ZR, together with the GA, IAA and ZR of high-content, soluble sugars worked more efficiently to induce new bulb formation.

      • KCI등재

        Simplified Analytical Model for Investigating the Output Power of Solar Array on Stratospheric Airship

        Yuanyuan Zhang,Jun Li,Mingyun Lv,Dongjie Tan,Weiyu Zhu,Kangwen Sun 한국항공우주학회 2016 International Journal of Aeronautical and Space Sc Vol.17 No.3

        Solar energy is the ideal power choice for long-endurance stratospheric airships. The output performance of solar array on stratospheric airship is affected by several major factors: flying latitude, flight date, airship’s attitude and the temperature of solar cell, but the research on the effect of these factors on output performance is rare. This paper establishes a new simplified analytical model with thermal effects to analyze the output performance of the solar array. This model consisting of the geometric model of stratospheric airship, solar radiation model and incident solar radiation model is developed using MATLAB computer program. Based on this model, the effects of the major factors on the output performance of the solar array are investigated expediently and easily. In the course of the research, the output power of solar array is calculated for five airship’s latitudes of 0°, 15°, 30°, 45° and 60°, four special dates and different attitudes of five pitch angles and four yaw angles. The effect of these factors on output performance is discussed in detail. The results are helpful for solving the energy problem of the long endurance airship and planning the airline.

      • SCIESCOPUSKCI등재

        Prediction of Pharmacokinetics and Penetration of Moxifloxacin in Human with Intra-Abdominal Infection Based on Extrapolated PBPK Model

        Zhu, LiQin,Yang, JianWei,Zhang, Yuan,Wang, YongMing,Zhang, JianLei,Zhao, YuanYuan,Dong, WeiLin The Korean Society of Pharmacology 2015 The Korean Journal of Physiology & Pharmacology Vol.19 No.2

        The aim of this study is to develop a physiologically based pharmacokinetic (PBPK) model in intra-abdominal infected rats, and extrapolate it to human to predict moxifloxacin pharmacokinetics profiles in various tissues in intra-abdominal infected human. 12 male rats with intra- abdominal infections, induced by Escherichia coli, received a single dose of 40 mg/kg body weight of moxifloxacin. Blood plasma was collected at 5, 10, 20, 30, 60, 120, 240, 480, 1440 min after drug injection. A PBPK model was developed in rats and extrapolated to human using GastroPlus software. The predictions were assessed by comparing predictions and observations. In the plasma concentration versus time profile of moxifloxcinin rats, $C_{max}$ was $11.151{\mu}g/mL$ at 5 min after the intravenous injection and $t_{1/2}$ was 2.936 h. Plasma concentration and kinetics in human were predicted and compared with observed datas. Moxifloxacin penetrated and accumulated with high concentrations in redmarrow, lung, skin, heart, liver, kidney, spleen, muscle tissues in human with intra-abdominal infection. The predicted tissue to plasma concentration ratios in abdominal viscera were between 1.1 and 2.2. When rat plasma concentrations were known, extrapolation of a PBPK model was a method to predict drug pharmacokinetics and penetration in human. Moxifloxacin has a good penetration into liver, kidney, spleen, as well as other tissues in intra-abdominal infected human. Close monitoring are necessary when using moxifloxacin due to its high concentration distribution. This pathological model extrapolation may provide reference to the PK/PD study of antibacterial agents.

      • KCI등재

        Characterization of Bacteriostatic Sausage Casing: A Composite of Bacterial Cellulose Embedded with ε-Polylysine

        Huixia Zhu,Shiru Jia,Hongjiang Yang,Weihua Tang,Zhilei Tan,Yuanyuan Jia 한국식품과학회 2010 Food Science and Biotechnology Vol.19 No.6

        The feasibility of a novel bacteriostatic sausage casing made of bacterial cellulose (BC) embedded with ε-polylysine (ε-PL) was evaluated. The ε-PL/BC composite was prepared by immersing BC tubes in ε-PL solution and its characteristics were analyzed with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD),and atomic force microscopy (AFM) techniques, respectively. The results suggested that ε-PL molecules were incorporated into the cellulose fiber networks and the ε-PL/BC composite might have a novel unique structure. No significant loss of antimicrobial activity was observed even after autoclaving at 121℃ for 30 min and the oxygen permeability was far below than that of polyethylene (PE) and polyvinyl alcohol (PVA) membrane. Its tensile strength was 51.8 MPa. The ε-PL/BC composite exhibits bacteriostatic and/or bacteriocidal activities against a broad spectrum of Gram-positive and Gram-negative bacteria; as a result, an extended shelf life than controls was observed for sausage packaged with the ε-PL/BC composite.

      • SCIESCOPUSKCI등재

        Simplified Analytical Model for Investigating the Output Power of Solar Array on Stratospheric Airship

        Zhang, Yuanyuan,Li, Jun,Lv, Mingyun,Tan, Dongjie,Zhu, Weiyu,Sun, Kangwen The Korean Society for Aeronautical and Space Scie 2016 International Journal of Aeronautical and Space Sc Vol.17 No.3

        Solar energy is the ideal power choice for long-endurance stratospheric airships. The output performance of solar array on stratospheric airship is affected by several major factors: flying latitude, flight date, airship's attitude and the temperature of solar cell, but the research on the effect of these factors on output performance is rare. This paper establishes a new simplified analytical model with thermal effects to analyze the output performance of the solar array. This model consisting of the geometric model of stratospheric airship, solar radiation model and incident solar radiation model is developed using MATLAB computer program. Based on this model, the effects of the major factors on the output performance of the solar array are investigated expediently and easily. In the course of the research, the output power of solar array is calculated for five airship's latitudes of $0^{\circ}$, $15^{\circ}$, $30^{\circ}$, $45^{\circ}$ and $60^{\circ}$, four special dates and different attitudes of five pitch angles and four yaw angles. The effect of these factors on output performance is discussed in detail. The results are helpful for solving the energy problem of the long endurance airship and planning the airline.

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